The metabolism and permeability of erythrocytes obtained from Duchenne (DMD) and myotonic muscular dystrophy (MMD) patients will be investigated in incubation experiments conducted in vitro. The premise underlying these studies is that the changes observed in erythrocytes may reflect alterations that are present in the muscles of these patients, since these myopathies are believed to be genetically-transmitted diseases involving cell membranes of various cell types. In order to verify earlier observations made with P31 NMR spectroscopy, the total phosphorus concentration in extracts of freshly drawn erythrocytes from patients and from normal individuals will be determined by analyzing extracts with standard photometric procedures. The basis for the apparently lower total phosphorus value in MMD erythrocytes will be explored by determining whether anion permeability may be altered; both radiosulfate influx and efflux will be evaluated. According to recent reports, phospholipase A2 activity and lysophosphatidylcholine (LPC) levels are raised in DMD. Since the agent, dipyridamol, is known to inhibit anion permeability as well as to stimulate lysophospholipase activity, the relationship between LPC levels (measured by thin layer chromatography) and sulfate permeability will be determined in the precense of this agent; erythrocytes from both patients and normal individuals will be examined. The influence of lysophospholipid addition on ion transport in vitro will be systematically examined.